Apparatus for conditioning crushed material



May 19, 1925. 1,538,192

v. G. LEAC H APPARATUS FOR CONDITIUNING CRUSHED MATERIAL Filed March 21,1924 2 sheets-sheet 1 2/ f1. g j I Vzzzazz' Gazde @ach May 19, 1925.

V. G. LEACH APPARATUS FOR CONDITIONINQQRUSHED MATERIAL Filed March 21,1924 2 Sl 1eets-Sheet 2 VE I Derzzozz (iarde e I {each Patented May 19,-1 925.

VERNON canon-amen, or omcaeo, rumors. 1

APPARATUS roa connirronme caosnan murmur;

Application filed March 21, 1924. Serial Ito. 700,787.

To all whom it my camera:

Be it known that I, VERNON GARDE LEACH,

a citizen of the United States, and a resi- I dent of the city ofChicago, in the county of Cook and State of Illinois, have inventedcertain new and useful Improvements in an A paratus for ConditioningCrushed Material; and I do hereby declare that the following is a full,clear, and exact descripaccompanyin tion of the same, reference beinghad to the drawings, and to the numerals of re erence marked thereon,which form a part of this specification.

This invention relates to an apparatus for-- conditioning granular orpulve'rulent materiall more particularly crushed or powdered O08.

not only for the reason that the efficiency of combustion isincreasedbut also because moisture in coal creates difficulties inconveying, handling, and storing.

Further, in pulverizing crushed. or granu- I lar coal,more power isrequired if the coal is moist.

In addition to the desirability of low moisture content, itisadvantageous to pass thecoarsely crushed coal to the pulverizers cold.One' of the great difliculties with all dryers on the market today isthefact that the coal is introduced into the pulverizer while hot. Whenhot, the particles of coal tend to adhere to each other and clog thepulverizer, transportation pipe lines, etc. Further, when a warm lump ofcoal is .broken it steams as the result of the .va-

porization of the moisture contained in the interior of the lump. Thissteam or water ,vapor then condenses on the cold walls of thepulverizer, ipe line and so forthand causes the pow ered coal to adherethereto. If, hgyever, the lump is cooled to at mospheric temperaturethis 7 vaporization does not occur.. Hence it is desirable not only todry the coal but also to cool it nearly to atmospheric temperaturebefore introducin it into the pulverizer. The coal shoul' therefore,beconditioned rather than merely dried.

Various methods and apparatus have'been proposed for ,drying coal. -Thusit has been proposed to use the heat from waste or chimney gases to drythe coal. This involvesnot only-diificulties in controllin the heat usedbut also occasions loss of V0 atile constituents,*danger of ignition ofthe pdwdered fuel and so forth. i

siderable proportion of water-vapor so that when cooled to atmospherictemperature dew will be deposited withthe resultthat if powdered coaldried by such ases is passed through a pipe line expose to theatmosphere dewlwill deposit on the interior of the pipe which dew willcause the coal to adhere tothe side of the pipe and"olog also-to reducethe moisture content'of the air or gas entrained in the crushed massbelow the dew point. This involves first Powdered coal should" be drywhen used much water. Most'oi the water may be re- 1 moved by air dryingat ordinary temperatures, while the remainder (usually some 2 'to 3'percent) is almost completely lost at 105 degreescentigrade.

The moisture which air or other gases can take up is a function oftemperature.

Waste 1 or chimney gases contain a con- Atmospheric air is rarelysaturated but its capacity to take up additional moisture is small. Ifthe air s heated, its capacity to absorb water vapor is reatlyincreased.

If heated air is passed through a mass of coal, the air takes up a partat least of the moisture of the latter and simultaneously heats up thecoal. It, therefore, air at atmospheric temperature is passed throu 11such heatedcoal the air is warmed there y andits moisture absorbingpower is increased.

Very-eflicientdr ying may be obtained by first passing heated airthrough the mass to eliminate a part of the moisture and simultanecuslyheat the coal and then passing air at atmospheric temperature throu hthe heated coalto utilize the heat of t e latter-in warmingthe' airsothat it is capable of readily absorbing the moisture in the coal inthe first stage of the process or for other useful purposes such asairfor combustion.

.The passage of air at atmospheric temperature through the crushed coalsweeps 15 crushed coal.

Figure 1.

out of the interstices in the latter any air having a high moisturecontent so that the air entrained in the final'product will not depositdew in any subsequent operation. In this condition both the crushedcoal-itself and the air surrounding the particles and entrainedtherein-are in substantial equilibrium with the prevailing atmosphericconditions so far astheir temperature and moisture contents areconcerned,

It is an object-of the present invention, therefore, to provideefificient, simple and readily-controlled "means for condltioninggranular or pulverulent material such as Other and further importantobjects of this invention will be apparent from the disclosures in theaccompanying drawings and the following specification.

The invention (in a preferred form) is I illustrated in the drawings andhereinafter more fully described. v

On the drawings:

Figure 1 is a vertlcal section through an 25 apparatus constructed inaccordance with the resent invention.

Figure 2 is a section onsthe line 2-2 of Figure 1. a

Figure 3 is a section on the line 3-3 of Figure 4 is a vertical sectionthrough a. mod'fied form of ap aratus.

As shown on the rawinfis: s The form of apparatus s own in Figures 1, 2and 3 comprisesacasing provided w1th an air inlet duct 11 and airdischargeduct 12 and a partition 13 adapted to prevent air passingdirectly from the duct 11 to the duct 12. The lower chamber formed bythe partition 13 is in communication with 5 through I the series of bars18 arrangedstep-wise I the eccentric the intake 14 of a centrifu 1 fan15. The discharge duct 16 of this i an is connected with the upperchamber of the casing.

Extending obliquely across the casing and for the material to betreated. This su port may conveniently be constructed on t e r principleof one or othe nof the well-known forms of mechanical stokerscomprisingf a or simultaneous movement by an eccentric 19.

. The crushed material 20 is fed onto this inclined support from ahopper 21 by means of a plunger 22 which is 'reciprocated by 19. A gate23 at the front of the hop or is provided to adjust. the amount of e1delivered to the support 17.

the end of the support 17.

Below' the artition 13 are arranged means for heating the air which isdrawn throu h the bed: of material from the duct ese means may be variedsuit vapartition 13 is a support 17 rying conditions. In man cases itwill be convenient to use heat exc angers, suchfor example as a seriesof coils 25 heated by steam, waste gases, etc. By this means the airdischarged by the fan 15 and forced upwardl through the bed of materialinto the discharge duct 12 is heated first by the warm bed of materialand second by the steam coils.

The passage of air directly from the duct 11 to the duct 12 over thelayer of material passing down the support 17 is prevented by means of aseries of shoes 26 pivotally supported by links 27. These shoes ride onthe upper face of the layer of material and may rise and fall with it.is

n the form of construction shown in Fi ure 4, the air is not passedtwice throug the bed of material with an intermediate heating operation.

In this case there are two inlet ducts 30 and 31 leading to the casing32, through which air may be passed by fans or blowers not shown. Whereair is introduced throu h both ducts the upper duct 30 contains eatexchanging means such for example as a steam coil 33 for heatin the airflowing therethrough. If waste hot gases are introduced through the duct30, the heating means may The air which passes throu h t e lower ductmay to advantage be use in combustion, in view of the heatit contains.

shown in Figures 1 to 3.

In the present art of furnace construction it has been found desirableto use hollow furnace wall's, air cooled, largely for their be omitted.

. In other respects, the construction is similar to that rotection. Suchair is used to support comsubstantial depth over said support, and

means for passing first a current of'heated gas and then a current ofunheated gas through the material as it passes oversaid support. 'At thelower end of the support a screw or other suitable conveyor 24 is.rovided' for, discharging the material as it rops ofi 2. An apparatusfor conditioning crushed material, comprising a support, means forpassing a continuous layer of material of substantial depth over saidsup ort, means for passing a current of u eated gas ilshrough thematerial as it passes over the. 1 ast art of said support :m'eans forheating t e current of gas after it has passed tioning I through thematerial and means for repass ing the gas so heated through thematerialas it passes over the first part of said support'.-

3. An apparatus for conditioning crushed material comprising a casing, asupport within said casin means for passing a continuous layer 0 depthover said support, a partition within the casing intermediate the endsof said support, a movable closure member adapted to rest upon saidlayer and rise and fall therewith to prevent the passage of gasesbetween the lowerjedge of said partition and said layer of material.

material of substantial ends of said support, and means for pass-.

ing currents of gases throu h said stream of materialp on either side 0said partition.

In testimony whereof I have hereunto subscribed my name in the presenceof two 26 subscribing witnesses.

Witnesses:

Rmsmu: Ems, Hmrwnsoo'rr Wanna PVERNONIGARDE LEAOHJ

